Radius arm pivot support



Oct. 15, 195? H. w. IHRIG RADIUS ARM PIVOT SUPPORT Original Filed Aug.27, 1954 INVENTOR E H R E G HAQVEY ATTORNEYS United States Patent (JRADIUS ARM PIVOT SUPPORT Harvey W. Ihrig, Odenton, Md.

Original application August 27, 1954, Serial No. 452,742. Dividgd andthis application June 30, 1955, Serial No. 519,2 4

2 Claims. (Cl. 33-174) (Granted under Title 35, U. S. Code (1952), see.266) The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without the payments of royalties thereon or therefor.

This application is a division of applicants copending applicationSerial No. 452,742, filed August 27, 1954, for Checking and LayoutMethod and Apparatus.

The present invention relates to a radius arm pivot support and moreparticularly to a radius arm pivot support for use in the accuratemeasurement of contour and profile gages, and for layout of workpiecesfor manufacture or tolerance check.

Commonly known methods and apparatus for layout or checking of gages andworkpieces are accurate for use only for small workpieces. Thislimitation is due to inaccuracies introduced both by human error andprecision instrument error when long lengths of sine bar are necessaryto measure angles of a large workpiece. Another deficiency of thepresent layout methods and apparatus is that a number of surface platesetups are necessary to locate the angular and radial surfaces of aproduct in a common plane.

The present invention overcomes the afore-mentioned limitations of knownmethods and apparatus for layout and checking of gages and workpieceseither for accuracy measurement or for manufacture by the presentationof a unique radius arm pivot support to be used in combination withlocator discs and a novel sine bar for locating various long lengthradii and angular surfaces of a product or gage evident in a commonplane. By the utilization of a radius center point as a reference point,only one master setup is required in order to measure or machine anarticle of manufacture to close tolerances.

An object of the present invention is to provide a radius arm pivotsupport for measuring or checking relatively long radii to withinprecision tolerance.

Another object is the provision of a pivot support which is constructedof precision parts to enable the assembled device to be a point fromwhich lineal measurements may be taken accurately.

A further object is to provide a pivot support having a precision balljoint between rotatable elements of the device such that rotation aboutthe pivot may be made without undue friction and without disturbingalignment of a supported article on the pivot support.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

Fig. 1 illustrates a plan view of a preferred embodiment of theinvention setup on a surface plate; and

Fig. 2 shows a side elevational view partially in section of a radiusarm pivot support.

Referring to the drawings, wherein like reference characters designatelike or corresponding parts througr out the several views, there isshown in Fig. 1, which illustrates the invention in operational layout,a surface Patented Oct. 15, 1957 plate 11 having a number ofperforations situated therethrough. Locating fixtures such as toolmakersbuttons 12, 13, 14, 15, 16, 17, and radius arm pivot support 18 aresecured to the perforations of surface plate 11 by suitable screws 20 toaccurately position for machining or measuring a workpiece 21, forexample, within an area defined by such fixtures and pivot support 18.

Radius arm 22, having an inner portion 22a and an outer portion 23, ispivotably mounted at inner portion 22a by pivot support 18 which isengaged to surface plate 11 or a remote position thereto to establishlong length radii on workpiece 21. Radius arm 22 may be supported at itsouter portion 23 by roller support 24 which enables the arm 22 to bearcuately swung on surface plate 11 with pivot support 18 as the centerpoint of the circle of the arc. Connected to the outermost end of arm 22is a bracket 25 which may hold a measuring gage 25a and a grinder 2512.

Details of the center pivot support 18 are shown best in Fig. 2 whereina base 26 is connected to surface plate 11 by means of countersunksetscrews 2t) circumferentially positioned in the base. A verticalstandard 27 is centrally disposed on base 26 to provide a mating surfacefor the upper surface or closed end 32 of an inverted cup member 28which is pivotably received thereon. A conical shaped counterbore iscoaxially positioned on the upper surface of standard 27 to receive aball or sphere 29 therein tangent to the wall 31 of the counterborewhereupon a portion of the ball protrudes a predetermined distance abovethe aforesaid upper surface of the standard and is maintained in apredetermined position by reason of the inclined wall of the conicalshaped counterbore in member 27. A mating bore or aperture is providedin the upper surface 32 of the inverted cup to allow the sphere 29 toextend therethrough into a cradle or recess 33 formed in the closed endof the .cup 28 thereby to contact the arm 22 and also to tangentiallycontact the wall defining the cup bore. Cylindrical walls 31a ofinverted cup 28 are positioned closely adjacent the wall surface ofstandard 27. The cradle 33 in upper surface 32.0f the inverted cup 23comprises a pair of oppositely disposed inclined walls arranged inparallel relationship and extending diametrically across the uppersurface of the cup and converging toward the aforesaid aperture thereinto receive the arm 22 thereon in a manner such that the central verticalaxis of standard 27 passes vertically through sphere 29 and arm 22, andthe arm 22 is contacted by the Walls of cradle 33. A verti cally-spaced,horizontal bar 34 is bolted by members 35 to the upper surface 32 ofinverted cup 28 to define a space within which arm 22 is clamped.

Radius arm pivot support 18 may be employed as follows, for example, inthe checking of a workpiece 21 for accuracy. Sine bar 36 is utilized tocheck the angularity of an edge 21a of the workpiece by layout of theprescribed angle. Layout is obtained by measuring proper lengths of theopposite and adjacent sides of the angle, space block 37 from pivotsupport 18 defining one side and either the sine bar 36 or an imaginaryline from center support 18 to fixture 13 defining the other side. Withthe known sides the trigonometric function of the desired angle can beutilized to check or lay out the angle.

Radius r of the front edge of workpiece 21 is checked or laid out byswinging the proper radius with arm 22 from center point support 18 andmeasuring the radius by gage 25a mounted on the end of arm 22 by bracket25. Reference locator fixtures 16 and 17 may be positioned toperiodically check the desired radius to which gage 25a is set. Tomaintain arm 22 parallel with plate 11, roller support 24 stations arm22 at the same height above surface plate 11 as does center pivotsupport 18.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

v /hat is claimed is: a

1. A radius arm pivot support comprising a base, a vertically disposedcylindrical standard integrally formed with said base at one endthereof, a cylindrical inverted cup having an end wall and a cylindricalwall slidably receivable over said cylindrical standard, a cradle formedin said endwall and having a pair of inclined walls, said cradleextending diametrically across the end WaL of said cup for receiving aradius arm, said cradle having a centrally disposed aperture formedtherein and defined by said inclined walls, a sphere for rotatablysupporting the cup on said standard, the other end of said standardhaving a centrally disposed bore in communication with said aperture andprovided with a conical Wall for receiving and maintaining said spherein a predetermined position within said bore such that the sphereextends through said aperture a distance sufliciently to engage theWalls defining the aperture and the radius arm disposed within thecradle whereby said sphere rotatably supports the cup on the standard,and means adjustably carried by said cup for clamping and maintainingthe radius arm Within said cradle in engagement with said walls definingthe cradle and with said sphere.

2. A radius arm pivot support comprising a base, a vertically disposedcylindrical standard integrally formed with said base at one endthereof, a cylindrical inverted cup having an end wall and a cylindricalwall slidably receivable over said cylindrical standard, a pair ofoppositely inclined walls symmetrically arranged on opposite vergingtoward the diameter and defining a centrally disposed aperture formedalong the diameter at the junction thereof for receiving a radius arm, asphere for rotatably supporting the cup on said standard, the other endof said standard having a centrally disposed bore in communication withsaid aperture and provided with a conical wall for receiving andmaintaining said sphere in a predetermined position within said boresuch that the sphere extends through said aperture an amountsufficiently to engage the Walls defining the aperture and the radiusarm disposed Within the inclined wall whereby the sphere rotatablysupports the cup on the standard, and adjustable means carried by saidcup in engagement with the radius arm for clamping and maintaining theradius arm in engagement with said pair of inclined walls and with saidsphere.

References Cited in the file of this patent UNITED STATES PATENTS1,153,092 McDermott Sept. 7, 1915 1,796,068 Van Der Meer Mar. 1t), 19312,369,425 Becker i. Feb. 13, 1945 2,371,048 Hayes Mar. 6, 1945 2,465,553Toth Mar. 29, 1949 2,489,733 Ullman Nov. 29, 1949 2,493,786 Swift Jan.10, 1950 FOREIGN PATENTS 1,090,934 France Feb. 18, 1952 487,895 CanadaNov. 11, 1952

